We thank Oliver Pybus, Andrew Rambaut, Rick Ree, Allen Rodrigo, and Wayne Maddison for discussion and valuable suggestions. We also thank Allen Rodrigo for providing hardware through his NIH grant #59174 and Don Gilbert for distributing PAL in his software archive. This work is also supported by a Bright Future´s Scholarship of FRST to A.D. and an Emmy-Noether-Fellowship of the DFG to K.S.